Belt joint and method of making same



Nov. 20, 1923., MLWW'M R. w. FULLER BELT JOINT AND METHOD OF MAKING SAMEFiled Nov. 14, 1922 Fatented Nov. 2%, 19233.

in r to it? r r i Prat .falbii U lililiQaEO MACHINE COMPANY, OFGEEENFIELD,

MASSACHUSETTS.

SSACEU'SETTS, A CORPORATION OF BELT JOINT AND FEET-HOD OF MAKING SA'ME.

Application filed November To all whom it may concern Be it known tnatl, RUFUS W. FULLER, a citizen of the United States, residing atDeerfield, in the county of Franklin and State of Massachusetts, haveinvented certain new and useful Improvements inBelt Joints and Methodsof Making Same; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as Wlll enableothers skilled in the art to which it appertains to make and use thesame.

This invention relates to a belt joint and more particularly to a beltjoint of the type illustrated in United States Letters Patent No.944,658, and to a method of making the same.

One of the objects of the invention is to improve the belt joint shownin said Letters Patent and to add to its strength and durability yetwithout increasing to an objectionable degree the thickness of the beltat the joint. A further object of the invention is to provide a methodwhereby the improved joint may be made in an easy and expeditiousmanner.

To the above ends the invention consists in the improved belt joint andmethod of producing the same hereinafter described and particularlypointed out in the claims.

In the drawings illustrating the preferred embodiment of the inventionFig. 1 is a plan of an abrasive belt showing the abrasive surface andthe locking fingers formed at j each end of the belt preparatory tojoining these ends together; Fig. 2 is a perspective view showing thebelt with the abrasive face downward and the fingers interlocked and inposition ready to be pressed into the back of the belt to form the beltoint; and Fig. 3 also illustrates in perspective the belt with theabrasive face downward and with the belt joint in the jaws of the pressby which the fibres of the fingers are pressed into the interstices ofthe fabric of the belt, a portion of the upper jaw of the press beingcut away for purposes of illustration.

Abrasive belts comprise, in general a body portion of firmly wovencanvas 01' other fabric or rubber, upon one side of which a surfacecoating of emery or other abrasive is adhesively secured. The endportions of the abrasive belt are joined to form anend- 14, 1922. SerialNo. 600,979.

less belt arranged to travel over pulleys in a well-known manner ingrinding machines,

the back or smooth surface of the belt com ing in contact with thepulley and the abrasive surface being positioned to engage the workbeing ground or polished.

Referring to the drawings, the improved belt joint is formed by meansoffingers 10 cut out or otherwise formed upon each end of the belt whichare interlocked and lapped over upon the back 1910f the belt. Heretoforeit has been the practice to soften the glue or cement by means of hotwater or steam'andthen to press the fingers firmly onto or into the beltbetween smooth surfaces. Such a joint, however, has been foundunsatisfactory not only because of its lack of strength and durability,but also because of the substantial increase in thickness at the joint.In the present invention, in order to secure a maximum gripping effectbetween the fabric of the fingers and the fabric of the back of the beltto thereby produce a belt joint capable of withstanding maximum strain,provision is made for removing the abrasive material from the surface ofthe fingers 10 as a preparatory step in forming the joint, so that whenthe fingers are lapped over upon the back of the belt, the contactingfabric surfaces, are in condition to be adhcsively and mechanicallysecured to each other in the most advantageous manner. A convenientmanner of removing the abrasive material is to pass the end of the beltsidewise beneath an emery wheel or similar grinding tool, care beingtaken that only the abrasive material is removed, leaving a surfaceadhesive upon the face of the fabric. The ends of th belt are thenbrought together and the fingers are interlocked and adhesively securedin a lapping position upon the back of the belt.

In addition, it has been found desirable, in order to produce a beltjoint. of maximum strength, to subject the fingers to the pressure of aknurled plate or similar device for forcing the individual fibres of thefingers down into the interstices or spaces between the fibres of theback of the belt to secure a mechanical gripping action between thefingers and the belt. This is of particular advantage in the case ofabrasive belts, for

- the reason that the fabric is so closely woven 'the interlockedfingers and the shearing strength of theadhesive or glue. In testingbelt joints formed according to the present method and those formedaccording to prior methods, such for example, as that disclosed in saidpatent, the improved belt joint has been found many times stronger. Inaddition to presenting a most desirable surface for the purposes ofadhesively securing the fingersto the belt, the removal of the abrasivesurface from the ends of the lingers assists in reducing the thicknessof the belt joint so that a joint may be formed of practically thethickness of the body portion of the belt itself.

According to the preferred manner of producing the improved belt jointfor an abrasive belt, the fingers 10 are died or out out of a strip ofabrasive cloth. One end of the belt is then placed upon a plate on agrinding table being positioned by pins proecting from the plate whichengage the bottoms of the spaces or notches between ad 'jacent fingers.The plate is then reciprocated on the table carrying the fingerstransversely back and forth beneath an emery wheel which grinds off theabrasive from the surface of the tapered ends and shanks of the fingerswithout removing it from the widened bases. The other end of the belt isthen similarly treated leaving the belt and fingersas shown in'Figure 1.The ends of the belt are then brought into a contiguous position andfingers l0 interlocked. The end end portions of the belt are then tackedor otherwise secured to a supporting frame 20 having a wire mesh 22 as asupporting surface. The surfaces of the fingers 10 from which theabrasive has ben removed and also the back of the belt are firstprovided with a priming coating of glue or similar adhesive and theframe 20 and belt are thereafterhung up to dry for several hours. Afterthe priming coating has dried, a second or thicker coating of adhesiveis applied to the surfaces of the'fingers and to the back of the beltand-the frame and belt are positioned between the jaws 9.6 of a press,(see Fig. 3). A. knurled plate 28 is interposed between the upper j awofthepress and the back of the belt, the belt being supported at the jointby the wire mesh 22, and the belt joint is then subjected to sufficientpressure to firmly impress or force the fibres of the fingers down intothe interstices of the fabric of the back of the belt to eifec't anactual mechanical 1 gripping between the fingers and the belt. I

desirable. The belt joint is permitted to reseveral hours until dry. IThe belt is then;

ready for use.

rLbelt joint formed in accordance with the present inventionhas no breakor interruption extending continuously across the belt. The ungroundbases on opposite ends of the belt meet at their edges or cornersleaving only small bare areas between the bases of the fingers, whichareas are separated from one another and are arranged in staggeredrelation so that for all practical purposes a continuous abrasivesurface at the joint is secured. 7

While the invention has been illustrated and described in its preferredform, it is to be understood that it may be embodied in other formswithin the scope of the following claims.

1. A belt joint for abrasive belts comprising interlocking fingers uponcontiguous ends thereof, from which fingersthe abrasive has beenremoved,leaving the original adhesive, the fingers being overlapped uponand adhesively secured to the back of the abrasive belt. V

2. A belt joint for abrasive belts comprisinginterlocking fingers uponcontiguous belt, the fingers being provided with a series of projectionsimpressed into the interstices oi the back oi: the belt to secure amechanical s'rip betweenthe fingers and "body portion- Zir the belt.

l. T he method of joining contiguous ends 1 of an abrasive belt whichconsists in forming fingers upon both ends of thelbelt, removing theabrasive fromthe fingers, interlocking the fingers applying adhesive tothe fingers and to the back of the belt, and thereafter subjecting thefingers to the pressure of a plate having projections thereon to impressportions o-f'the fingers into the interstices of the back of the belt. 7

The method of joining contiguous ends ofan abrasive-belt whichconsistsin forming fingersupon both ends of the belt, grinding off @the abrasivefrom the fingers without .removing the original adhesive, interlockinand overlapping the fingers upon thebac of the belt', applying adhesivetothefingers and back of the belt, and thereafter subject ing thefingers to pressure to secure them to the back of the belt.

6. The method of joining contiguous ends 01 an abrasive belt whichconsists in forming fingers upon both ends of the belt, removing theabrasive from the fingers, interlocking and overlapping the fingers uponthe back of the belt, applying adhesive to the fingers and back of thebelt, and pressing the joint between rough surfaces to cause the fingersand belt to interlock at separated points.

7 The method of joining contiguous ends of an abrasive belt whichconsists in forming fingers with tapered ends and \videned bases uponboth ends of the belt, grinding of? the abrasive material from theshanks and tapered ends of the fingers Without removing it from thebases, interlocking the fingers With the unground bases on the oppositeends of the belt meeting, applying adhesive to the fingers and to theback of the belt, and pressing the fingers and belt into close contact.

RUFUS W. FULLER.

